1. Field of the Invention
This invention generally relates to device for providing efficient electrical connection with a generally planar conductor covered with an insulating layer such as paint, rust or stain.
2. Description of the Related Art
There can be various types of electrical connections between conductors. A grounding cable is often connected with an enclosure of a switchboard. A linear conductor is connected with another linear conductor by corresponding terminals. A conductor is connected to a terminal base of a distributor or a planar terminal of an electrical appliance. A large capacity transformer utilizes surface contact between two plate bars. Cables are connected to terminals of a battery. There are numerous other possible connections between conductors.
Such electrical contacts or connections are often hindered by insulating hazards covering contact portions such as paint, dust or rust. Mere connection with a conductor surface painted with insulating paint for pleasing appearance or rust inhibition often renders the connection electrically insufficient. Dust or rust may also inhibit sufficient electrical connections.
To provide an electrically sufficient connection with a planar conductor covered with an insulation layer, an appropriate portion or area on a conductor surface needs to be pretreated or scraped with a file or screwdriver for example. It is very time consuming to provide sufficient scraped areas on a large or complicated appliance, especially if there are many portions to be treated.
Some members of a complicatedly designed appliance cannot be easily or properly grounded partly due to their relative inaccessibility. It is often wishfully expected that ungrounded members of an electrical device will provide indirect grounding by the mere fact that they somehow contact grounded members, which is often proved to be a serious error.
A similar problem arises between a cable conduit and electric cables housed therein. A cable conduit is often made of a conductive material such as a metal, which is generally indirectly grounded or expected to be grounded through conductive portions of an electric apparatus to which the cables in the conduit are connected. However, such grounding is not actively constituted, thus often proving to be insufficient.
There exist a number of makeshift ways to provide grounding where such electrical connections are not originally created, such as by utilizing frames or bodies of electric appliances. Of course, originally constructed electrical connections can be made between electrical cables and terminals of electric appliances, between two flat bars where large current is involved, or between batteries and cables. Those originally created contact areas are generally prepared of copper or aluminum, which are prone to rusting, staining or dusting, possibly adversely affecting electrical connection therewith. To provide reliable electrical conduction between elements, it is often required to remove such insulating substances from the contact areas before electrical connections are made.
Accordingly, it is an object of the present invention to provide devices and tools with which to accomplish efficient and easy removal of insulating substances from portions of conductor surfaces, preferably concurrently with making electrical connection therewith.
A device of the present invention is generally a conductive threaded element having a serration portion which scrapes or clears a generally planar surface portion of a conductor plate. This invention additionally provides conductive intermediate members to further efficiently provide electric connection with a planar conductor.
Such a threaded device may be a bolt structure having a serration portion. The serration portion scrapes a surface area of a conductive material or conductor plate covered with an insulating substance as the bolt device is further fastened into a threaded hole provided in the conductor plate to clear or remove the insulating substance from the surface area.
Such a threaded device may be a nut element having a serration portion. The serration portion scrapes a surface area of a conductor plate covered with an insulating substance as the nut device is tightened and turned with a bolt to remove the insulating substance from the surface area.
Alternatively, such a threaded device may be a washer element. The serration portion scrapes a surface area of a conductor plate covered with an insulating substance as the washer is pressed against the surface and turned on the surface to remove the insulating substance from the surface area.
Such a threaded device may be a combination of a threaded structure and a washer element having a serration portion. The serration portion scrapes a surface area of a conductor plate covered with an insulating substance as the washer is pressed and turned on the surface by the threaded device when the threaded device is further screwed through a threaded hole provided in the conductor plate to remove the insulating substance from the surface area.
A tool or scraper device with a serration portion may also be provided to directly and conveniently provide scraping of a conductor surface area. A variety of tool members are additionally provided to accomplish easier and improved scraping of a conductor surface area.
Several embodiments of the invention are shown and described herein, and the basic characteristic aspects of this invention will be set out here briefly for the types of devices disclosed.
Serration Member
A conductive serration member is provided as a metal plate, such a copper plate, having a serration portion along a longitudinal edge, which is to be made into a single-layered or multi-layered cylindrical ring having a serration along an edge. The serration portion may advantageously be a plurality of {circumflex over ( )}-shaped teeth. The serration member should be hard enough to efficiently scrape and clean paint or rust from a conductor surface portion when pressed and turned against the surface portion. It is not essential but advantageous that the serration member is also deformable and flattened to provide efficient electric connection after the scraping operation by providing a large contact area with the scraped conductor surface area. When a cylindrical serration member is utilized, it is advantageous that all such deformation of the serration is provided toward the inside of the cylinder. If the serration member is made of a shape memory alloy, when deformed through a use it can be restored and utilized again by appropriate heating of the deformed serration body.
A conductive threaded device may be a bolt element having a serration member provided around its bolt shaft under its bolt head to form a serration device. The serration device is pressed against a surface of a conductor plate covered with an insulation substance as the bolt element is further screwed into a threaded hole provided in the conductor plate, scraping a surface area to remove the insulation substance from the surface area and provide efficient electric conduction therewith. The threaded device may alternatively be a nut element having serration member as a serration device on its surface contact face.
Washer Device
A conductive washer device has a serration element on a face. The serration element on the washer device can be turned with a bolt engaging the washer device and scrapes a conductor surface area covered with an insulation substance. The serration element is eventually deformed substantially xe2x80x9cflatxe2x80x9d on the conductor surface. The washer device can be independently used as a file if so desired.
Washer-Incorporated Threaded Device
A conductive washer-incorporated threaded device incorporates a washer element. The threaded device can be a bolt structure or a nut structure. This washer-incorporated threaded device provides easier and more efficient operation on a conductor surface covered with an insulating substance.
Device and Terminal Plate
A connector device is mainly used to ground a cable conduit by electrically connecting the conduit with the body portion of a switchboard or distributor. One such connector device utilizes a terminal plate to detachably mount a nut device to provide flexibility in size adjustment as cable conduits generally come in a variety of sizes.
Scraper Tool Device
A scraper tool device provides scraping of a conductor surface area covered with an insulating substance, including a serration portion and a grip handle. The tool provides handy and quick scraping of a conductor surface portion for improved electrical connection. The serration portion is gradually deformed, providing a constant and secure scraping on the conductor surface.